The thermoforming process is a common method of forming trays for food packaging. Various materials have been used, in rollstock form, as a feedstock material for forming trays for food packaging. One example is the foamed polystyrene tray used in the packaging of fresh red meat. In this end use, the tray forms a support for the meat product, and is typically overwrapped with a clear thermoplastic sheet or film.
Current marketing and distribution practices in the sale of food products, and particularly meat products, have put an increasing demand on the packaging materials to provide needed shelf life. Therefore, packaging in which oxygen transmission rates are lowered is especially in demand in the case of oxygen-sensitive products such as fresh red meat.
It is object of the present invention to combine low oxygen transmission rates in a packaging system coupled with the advantages of foamed or unfoamed polystyrene or other thermoformable plastics.
It is a further object of the present invention to provide such a combination in which the resulting sheet is thermoformable or useful in vacuum skin packaging (VSP) techniques.